I am a mother of 3 who works full time and breast fed all 3 of my babies. With my first child I never really found a bottle that worked. Either he wouldn't take one or if he did it would give him an upset tummy. With my second child I tried a couple and then found the Soothie bottles by The First Years. These were by far the best bottle for my baby. She easily transitioned to the bottle once it was time to go to the babysitters all day. I froze my milk for her during the day and nursed at night and there were no problems at all. She never refused this bottle or had any gas or upset tummy problems....